M.Ing. (Civil Engineering) / Variable EI, post tensioned continuous bridge decks frequently occur in practice. The design of such a deck is essentially a process of trial and error. The aim of this thesis is to facilitate the design process by eliminating the sting from the otherwise complex flexural analysis by the development of suitable PC programs. This thesis will focus on the following three main issues: 1 SECTION PROPERTIES The program PROP presents a minimum input approach for the determination of uni-axial section properties. Special enP1aSis is placed on the section efficiency factor, being a direct quantitative measure of a sections flexural ability, ranging from 0 to 1. The effect of this factor on partial prestressing is also discussed. 2 THE MAGNEL DIAGRAM The program MAGNEL presents a linear programming optimisation aid for the design of uneracked sections (i.e. Classes 1 and 2 prestressing). The following is catered for: • variable prestress loss • both sagging and hogging moments • composite construction • two stage stressing • secondary moments due to prestressing The effects of the section efficiency factor, area redistribution and secondary moments on the Magnel diagram is also evaluated. 3 VARIABLE EI CONTINUOUS SPAN ANALYSIS The program BEAM presents a transparent finite element approach for the evaluation of bending moments, shears and deflections for variable EI continuous spans. The following features are available: • for a single span, supports may be fixed, supported or free • up to a six span continuous structure may be analysed • loading may consist of point loads, moments, uniformly distributed loads, support deflection or prestressing The direct prestressing input feature is compared against the equivalent load method for a varying parabolIe tendon force as developed by Catchick. The formulation of the Catchick method is also simplified by the introduction of additional parameters.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:3791 |
| Date | 11 February 2014 |
| Creators | Bijker, Wolter |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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